Electromechanical "suitcase" or "stage" pianos are carried by professional pianists from job to job, with the great advantage that the exact same instrument is played each night. This means, however, that the piano must be able to withstand large shocks, both mechanical and thermal. A mechanical shock will occur, for example, when the piano is dropped. As an example of a thermal shock, let it be assumed that the pianist is carrying the piano in the trunk of his car on the desert and that the temperature within the trunk is over 200 degrees F. The pianist then parks at an airport and boards a jet plane, where the temperature in the baggage compartment is soon about minus 70 degrees F.
Not only must the piano be so constructed as to withstand the indicated shocks, but its keyboard must be able to take--without breakage or any substantial wear--millions of heavy blows such as are often imposed by rock musicians. In addition to being substantially immune to wear, it is a distinct necessity that the shanks do not tend to bounce off the balance rail as the outer portions are hammered.
A further and extremely important requirement is that the keyboard be quiet. There should be no substantial clicks, rattles, rubbing sounds, etc., so that the only thing heard by the pianist and those around him is the music. This requirement, and others stated herein, are of course applicable not only to electromechanical pianos but also to acoustic pianos and similar keyboard musical instruments in which the present keyboard may be employed.
Another major requisite of keyboards is that they be quickly mass-producible with great precision, low cost and few parts. When it is considered that there are as many as 88 keys in each instrument, the saving of even a few seconds relative to each key is a substantial item. It is of major importance that the keys be quickly and easily removable from and then replaceable in the instrument, and that there be no requirement for replacing of the key in the exact same position it previously occupied.
The keyboard should, both to the musician and to service men, have the same general mode of operation, assembly and re-assembly as has been familiar in wooden keyboards for many decades. Thus, for example, there should be pins which actually project upwardly into slotted shanks--but without the severe noise, wear, cost and other factors characteristic of keyboards with wooden shanks and metal pins. The pin-in-slot construction permits mounting and removal of the keys in seconds, without making any connections or disconnections.
To state an additional requirement--one especially applicable to suitcase electric pianos--there must be lightness. Thus, for example, the elimination of one whole sheet of strong, heavy plywood is important. Not only is weight reduced, but cost is brought down by a major factor.
Of course, it is essential that the keyboard play well--"feel" very good to the musician. He is highly interested in touch, balance, inertia, etc. With regard to touch, it is pointed out that different pianists have different requirements in that some like it light and others heavy. To achieve--at almost no added cost--a piano whose touch may be changed in a manner of minutes by a dealer, in order to satisfy a particular buyer, is an important accomplishment. Very importantly, the weight of each key must be substantially the same as that of each other key. Then, there will be the same feel or touch sensation at each and every key. Such touch should be similar to that of a wooden keyboard.
There are a large number of prior-art patents which describe piano keyboards made of synthetic resin, metal, and combinations thereof. However, to this day the piano keyboards commercially produced by all manufacturers known to applicant are primarily wood. In particular, the shanks are sawed from wood. The balance pins and guide pins are steel driven into maple, and there are numerous bushings which are laboriously inserted into the shanks. Wear is a major problem, as are cost, noise, and various others of the factors listed above.
The present keyboard is believed to be the first to solve all of the above (and other) problems, and to be the first synthetic resin piano keyboard which has high quality and is also capable of being easily and economically mass-produced.